Pesticides



United States Patent 3,218,147 PESTICIDES Ronald Frederick Homer, Wokingham, England, assignor to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain No Drawing. Original application June 29, 1960, Ser. No. 39,461, now Patent No. 3,119,831, dated Jan. 28, 1964. Divided and this application Aug. 27, 1962, Ser. No. 226,192 Claims priority, application Great Britain, July 10, 1959, 23,759/59 1 Claim. (Cl. 712.3)

This application is a division of my copending application, Serial No. 39,461, filed June 29, 1960, now U.S. Patent 3,119,831.

This invention relates to new amidines which possess herbicidal properties, and to herbicidal compositions containing them.

The invention provides amidines of the formula:

where R is a substituted-or unsubstituted phenyl radical, or a pyridyl radical; R is a hydrogen atom or a methyl radical; R is an aliphatic hydrocarbon radical having from 4 to 12 carbon atoms; and R is a hydrogen atom or an aliphatic hydrocarbon radical, provided that where R, is an aliphatic hydrocarbon radical the sum of carbon atoms of R and R taken together is not greater than 16; and acid addition salts of said amidines.

Where the group R is a substituted phenyl radical the substituent can be, for example, one or more of the following: an atom of a halogen for example chlorine; a lower alkyl radical, for example methyl or ethyl; and a lower alkoxy radical, for example methoxy or ethoxy.

Compounds of particular interest because of their herbicidal properties are those in which R, is a hydrogen atom.

In general the compounds of the invention which show pronounced herbicidal activity are those in which the total number of carbon atoms contained in groups R and R taken together is from 4 to 10 (especially where R is a hydrogen atom).

The invention also includes a process for the preparation of amidines in which a compound of the formula:

is reacted with an aliphatic amine of the formula:

where R R R and R have the meanings given to them above, and R is a lower alkyl radical for instance methyl or ethyl. The process can be performed using a simple mixture of the reactants, or by using the reactants 3,218,147 Patented Nov. 16, 1965 "ice in a suitable solvent or diluent such as a lower alkanol, for instance ethanol; or a hydrocarbon solvent, for instance, toluene or benzene. The temperature at which the process is performed depends largely upon the reactivity of the reactants and, where a solvent or diluent is used, upon the nature of that solvent or diluent. In general the preferred temperature is from C. to 150 C. With regard to the proportions of reactants used, it has been found convenient to use the amine in slight excess.

Since the compounds of this invention show herbicidal activity, the invention also includes herbicidal compositions containing as active ingredient, an amidine of the invention or an acid addition salt thereof. The composition can, for example, be a liquid composition obtained by dissolving or dispersing the active ingredient in a suitable liquid, for example water or an organic liquid. The compounds of the invention are, in general, not soluble in water to an appreciable extent, and thus aqueous solutions are not readily prepared. Satisfactory aqueous compositions, however, can be prepared by dissolving the compound in a suitable organic solvent, for example methanol, tetrahydrofurfuryl alcohol, fi-ethoxyethanol, ethylene glycol, an alkylated benzene or kerosene. The herbicidal composition can be in the form of a powder in which the active ingredient is in admixture with a powder diluent. The pesticidal compositions, whether liquid or powder, can contain a wetting or dispersing agent to facilitate their use as spray compositions.

The invention also includes a method for the destruction or control of vegetation, in which the vegetation is treated with a herbicidal amount of a compound or herbicidal composition as described above.

The invention is illustrated by the following examples in which (unless otherwise stated) the parts referred to are parts by weight. I

EXAMPLE 1 This example describes the preparation of N-phenyl- N'-n-hexylformamidine.

A mixture of O-ethylisoformanilide (15 parts: 1 mole) and n-hexylamine (11 parts: 1.1 mole) dissolved in toluene (50 parts) was heated under reflux for-2 hours. The toluene was then removed by distillation under reduced pressure leaving an oily residue from which was distilled N-phenyl-N-n-hexylformamidine, B.P. 132 C./0.3 mm.

EXAMPLE 2 This example describes the preparation of N-m-chlorophenyl-N'-n-'octylformamidine. v

A mixture of m-chloro O-ethylisoformanilide (9 parts) and n-octylamine (6.8 parts) dissolved in toluene (20 parts) was heated under reflux for 2 hours. The toluene was then removed by distillation under reduced pressure leaving a residue from which was distilled N-m-chlorophenyl-N'-n-octylformamidine, B.P. 162-170 C./ 0.5 mm.

EXAMPLES 3-10 A number of other N-phenyl formamidines (shown in Table 1 below as Examples 3-10) were prepared by the process of Example 1 but using the appropriate aliphatic amine instead of the n-hexylamine used in that example.

q A 3 J T able 1 ing a residue from which was distilled N-phenyl-N'-d0decylacetamidine, BP. 150-160 C./0.001 mm.

i g Compound gg g EXAMPLES 44 AND 45 5 Two other N-phenyl acetamidines (shown in Table 3 N-pl1enyl-N-u-butylformarnidine 104-106, 0. 1 NDMHYIN, n octylformmnimnk 1284381101 below as Examples 44 and 45 were prepared by the proc N- twn tt i-ndecylfornramidirge 1523-1624003 ess or Example 43, but using n-hexylamine and n-octyl- N-p ienyl-N -n-dodecylforrnan1i inc .2 70-1." 0075 mmmm mom lomim 35 amine respectively instead of n dodecylamlne. Nphenyl-NQN-di-n-butyl lorn1amidiue l 115-120/0. 25 N-phenyl-N,N-di-is-butyl lorlnamidineflr 100*102/0. 1 l0 N-phenyl-N,N-di-n-amyl formamidiue. 13U138/O.25 Tabl 3 Compound Boiling point EXAMPLES 11-42 N -phenyl-Ni-n-hexylacetarnidine. 114-120/ 0 A further large number of N-phenyl formamidines sub- N'PhQHYIN 1304354 stituted in the phenyl radical are set out below in Table 2 as Examples 1142. These substances were prepared by processes analogous to that described in Example 1, but using the appropriate substituted O-ethylisoformanilide instead of O-ethylisoformanilide, and using the appropriate aliphatic amine instead of n-hexylamine.

Table 2 Compound B oiling point (C./mmi) N0'eh10rophenyl-N-n-l1exylformamidine. 140-148/0. 25 N-o-chlorophenyl-N-n-octylformamidine 164-170/ 25 N-m-chloropheny1-N-n-hexyl[ormamidine l 131"145/ 25 N-m-chloropheuyl-N-n-octylformarnidine. 162-170/ Np-cl1lorophenyl-N-n-l1exylformamidine..7 136-144/ 1 N-p-chlorophenyl-N-n-octylformamidine 162 1G4/ 25 N? ,4diehl0rophenyl-N-n-hosylformami- 168-174] 4 no. N-3,4-dichl0r0phenyl-N rm-octydformamt 168-174,

dine. N-Z,4-dichlorophenyl-N-n-butyltormami- 182'13G/ 05 me. N ;12 ,4-dichlorophenyl-N-n-oety1tormami- 168-174/ 05 me. Nzii Azfi-trichlorophenyl N -n-butylformami- 144-148/ .025

me. N-2,4z5-trich1orophenyl-N-n-octylformam- 164/ .005

idine. N-o-tolyl-N n-butyl formamidine 105410] .25 N-o-tolyl-N-n-hexylf0rmarnidine, 128-136/ .05 N-o-tolyl-N-n-ootylorrnamidine 172-175] .1 N-m-tolyl-N n-her 130140/0. 1 N-p-t olyl N-n-hexy llormamidine 1464 52/0 1 N-p-tolyl-Y-n octylformamidine 174-l78/O. 1

N-2 ,Sdimethylphenyl-N-n-buty1l0rma1r1i- 110-120/ .01

me. N-2 ,G-dimethylphenyl-N-n-hexyltormami- 147/154/ .8

me. N-2,6dimethylphenyl-N-n-octyltormami- 154-158/0.

dine. N -2,4dimethylpheny1-N n butylt'ormami- 114-121/0. l

dine. N-QA-dimetbylphenyl-N-n-hexy1t0rmami- 128-140/ O7 5 dine. N-2,3-dimethylphenyl-N-n-butylformami- 114-123] O5 dine. N-2,B-dimethylphenyl-N-n-hexylformami- 143-147/ 05 dine. N -2,5-dimethylphenyl-N-n-buty1formemi- 116-124/ 18 dine. N-2,5-dimethylphenyl-Nm-hexyllormami- 140*145/ 02 dine. N-3,4dimethylphenyl-N-n-butyltormami 130-134/0. 25

dine. N-3Adimethylphcnyl-N-n-l1exylformami- 120-133/0. 1

dine. N-peth0syphenyl-N-n-hexylformamidine a 164-170/0. 5 N-p-dimethylamin0phenyl-N-n-buty1torm- 90/ 005 arnidine. N-p-dimethylaminophenyl-N-n-octylform- 140/ .005

amidine.

EXAMPLE 43 This example describes the preparation of N-phenyl-N- dodecylacetamidine.

A mixture of O-ethylisoacetanilide (8.2 parts) and ndodecylamine (6.8 parts) dissolved in toluene (25 parts) was heated under reflux for 2 hours. The toluene was then removed by distillation under reduced pressure leav- EXAMPLE 46 This example describes the preparation of N-2-pyridyl- N-n-butylformamidine.

A mixture of 2 ethoxymethyleneiminopyridine '(7 parts) and n-butylamine (4 parts) was dissolved in toluene (25 parts) and the resultingnsolution heated under reflux for 2 hours. The toluene was then removed by distillation under reduced pressure and the residue distilled to give N-Z-pyridyl-N'-butylformamidine, Bl. 176180 C./ 18 mm.

EXAMPLES 47-49 Three further N-2-pyridylformamidines, shown in'Table 4 below as Examples 4749) were prepared by the process of Example 46 but using the appropriate aliphatic amine instead of the butyl amine of that example.

Table 4 Example Compound Boiling point; No.

N-2-pyrldyl-N-n-hexylf0rmamidine 124-130/0. 1 N -2-pyridyl-N -woctyll0rmamidine 168-172/0. 1 N2-pyridyl-N-n-dodecyll0rmamidine 178-182/0. 001

The herbicidal properties of a large number of amidines of this invention are illustrated by the screening tests described below in which the compounds have been tested as herbicides by being sprayed in the form of liquid compositions on the following plant species: Wheat (Triticum spp.), wild oats (Avena spp.), mustard (Brassz'ca alba), kale (Brassica oleracea), sugar beet (Beta vulgaris), red clover (T rifolium pratense) and cleavers (Galium aparine).

The herbicidal compositions tested were liquid compositions containing 0.05 lb. of amidine as active ingredient per gallon of Water and the compositions were applied to the test plants at the rate of gallons/acre, i.e. the active ingredient was applied at the rate of 5 lb./acre. The compositions contained also 0.3% by Weight of a wetting agent consisting of a 27% aqueous solution of the condensation product of one mole of octyl cresol with 7-8 moles of ethylene oxide. Where the amidine used was water-soluble, the liquid composition was made simply by dissolving the amidine and the wetting agent in water; but amidines not sufliciently soluble in water were first dissolved in a small quantity of methanol and the resulting solution mixed with sufficient Water to provide a liquid composition containing 0.05 lb. of amidine/ gallon of Water. Q

The results obtained are set out in Table 5 below in which the herbicidal activity of each of the compounds tested has a grading number from 0 to 4. These grading U 3,218,147 5 6 numbers relate to the effect of the test compounds on the phenyl and pyridyl; R is selected from the group consistplants sprayed and have the following meanings: ing of hydrogen and methyl; R is alkyl of from 4 to 12 complete i11 carbon atoms; and R is selected from the group consist- 1 Very severe damage with partial kill. ing of y g n y P E t here R i 2 Severe damage. lkyl, the sum of carbon atoms of R and R taken to- 3 Moderate damage. gether is not greater than 16, and the herbicidally etfec- 4 Slight damage. tive acid addition salts of said compounds.

Table 5 Compound of Wheat Wild Mustard Kale Sugar Red Cleavers Example N0. Oats Beet Clover Meow-wot:-use:axe-mummew-xnmuw-wmcncewmuzww-mwwmmwzooecaww toMacenib-wet:musesmtma-tewwmwmwcnwmmmeopwmwwwwwwcoozoo Hut-Hessewe:u uzmtecmmssvoacnmwmtm-nwwowmwooooocoow cmsnowmenmtmmcoussmmcnuswmwi-maw-mowwmiwowtwowu v- Moscow-mince.threesome-us-rwmcowmreausmrmwmwwomuswoow automatonsw-w-uswwmwmwww-uzmmwceeoeaww-zowwwlotwwwmmvm wwwmmAw-www-wwmtawiwew usnwvwwwwwwmwwrwwmwrcn *Compound applied at the rate of 2-1b./acre.

What I claim is: References Cited by the Examiner A il g f the j? P 3 of fi f iggi UNITED STATES PATENTS in w e vege a ion is rea e Wl a er 1c1 3,073,851 1/1963 Ste1gcr 260296 amount of a compound selected from the group consisting 3,084,192 4/1963 Smathers 71 2.6

of compounds having the formula:

FOREIGN PATENTS R3 498,090 l/1939 Great Britain. OTHER REFERENCES Mandel et al.: J. Am. Chem. Soc., 76, pages 3978-82 wherein R is selected from the group consisting of LEWIS GOTTS,PrimaW Examinerphenyl, chlorophenyl, lower alkyl phenyl, lower alkoxy JULIAN S. LEVI'IT, Examiner. 

